thanks Keith. Yeah, I had to think long and hard about ALL the walls a while ago.
Lets see...
The exterior walls of the entire space (basically, the side walls separating us from our neighbors, the karate studio and a sporting goods store), these walls are double sheetrock with a sound channel on our side and insulation. The framing General, as I call him, has built some recording studios in the past, and his examples of what he has done in the past matched what I have learned and read on this forum, books, etc. He basically is constructing the walls so nothing on our side is touching the walls of our neighbors. So, the side walls of the store will be fine for the general noise associated with a music store that gives lessons.
The lesson rooms, which are separate and not attached to the side walls of the store, are single layer sheetrock with a sound channel. You will be able to hear the lessons somewhat, but I'm fine with that. Our current lesson studio has rooms that were very poorly put together (the former owner did this, not me) and these rooms work fine. When you stand outside of them, you can hear the lessons, but when inside them playing an instrument, you can only hear yourself and not the other rooms. The ceiling is single layer sheetrock with a sound channel and insulation.
As for my recording studio, this is an entirely separate room built within the store. These walls are double sheet rock on both sides, a sound channel on one side, and staggard stud. The floor is not floating, but I will be building a drum riser to help lessen the sound transmission from the drums. There will be 2 amp closets as well for loud guitarists rocking out...perfect for my band.
The ceiling is 2 layer sheetrock with a sound channel and insulation.
So, to answer you questions Keith:
1 and 2. The contractor and myself no as much about soundproofing as we've learned from reading and a little real-world experience. I have built a recording studio as well, which was double layer sheet rock on both sides and insulation on staggered studs. However, I did not use a sound channel and the sound proofing of the door frames left little to be desired. I have learned from those mistakes...hopefully. This new studio is not the next Paisley Park, but it will do for students and amateurs...with the occasional pro musician that wants to save a buck or two.
3. I think I described the walls above...the studio is basically a room within a room, the roof of the building is a standard commercial roof.
4. I will have to get back to you regarding the noise ordinances, but most of the recording studio projects will be happening after business hours, as not to affect the other businesses.
5. There is no language whatsoever in the lease regarding noise levels. Our landlord, a single person (not a mega-reality company) who owns the building and is helping us with bidding out jobs, etc. He is fully aware of the sound issues with a music store, so he has worked with myself, the architect and the framing general to make sure the walls are as good as they need to be...without spending hundreds of thousands of dollars.
I hope that answers your questions. Take from that what you will and let me know what you think.
thanks again,
Jordy A.
Alarm bells are ringing in my head. 
